In Deployment: Directory Based Edge Blocking for Exchange Online Protection

Hey Wendy! We are currently on Wave 15 with FOPE, EOP (as a passthrough mostly) and we have Dirsync running. We use the Secure FTP to upload the list of internet routable email addresses to FOPE. All of our mailboxes are on Office 365 with the exception

of a few on premise Exchange mailboxes and a ton of Unix mailhosts and lists. I have a three questions. How do you restrict mail enabled objects in the directory that you don't want to receive email from the internet, but that you want to be open for internal

use. For example, I have an site email list that I can't restrict because a Unix mailhost might email it. That Unix mailhost is not in my directory. I also don't want this list to receive email from the internet. On the flip side, I have some Unix mailhosts

that I want to receive email from the internet. Do they need to have mail enabled users (or Contacts) in Active Directory or can they be added using the User Source List? Lastly, does DBEB and Authoratative prevent you from emailing anything that might reside

on-premise that is not in Windows Azure Active Directory or will it still forward unresolved addresses in to our Unix smarthost? Thanks!